This feature is experimental. It may be changed or removed in a future version.
This layer's location URL.
If the layer has no visible history, this property still returns the URL of the content in the overlay. In this case the browser's address bar will show the location of an ancestor layer.
When this layer opens a child layer with visible history, the browser URL will change to the child layer's location. When the child layer is closed, this layer's location will be restored.